target: Fix ordered task target_setup_cmd_from_cdb exception hang

If a command with a Simple task attribute is failed due to a Unit
Attention, then a subsequent command with an Ordered task attribute
will hang forever.  The reason for this is that the Unit Attention
status is checked for in target_setup_cmd_from_cdb, before the call
to target_execute_cmd, which calls target_handle_task_attr, which
in turn increments dev->simple_cmds.

However, transport_generic_request_failure still calls
transport_complete_task_attr, which will decrement dev->simple_cmds.
In this case, simple_cmds is now -1.  So when a command with the
Ordered task attribute is sent, target_handle_task_attr sees that
dev->simple_cmds is not 0, so it decides it can't execute the
command until all the (nonexistent) Simple commands have completed.

Reported-by: Michael Cyr <mikecyr@linux.vnet.ibm.com>
Tested-by: Michael Cyr <mikecyr@linux.vnet.ibm.com>
Reported-by: Bryant G. Ly <bryantly@linux.vnet.ibm.com>
Tested-by: Bryant G. Ly <bryantly@linux.vnet.ibm.com>
Cc: stable@vger.kernel.org # 4.4+
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

1 files changed, 0 insertions, 1 deletions

diff --git a/include/target/target_core_fabric.h b/include/target/target_core_fabric.h
index de44462a7680..5cd6faa6e0d1 100644
--- a/include/target/target_core_fabric.h
+++ b/include/target/target_core_fabric.h
@@ -163,7 +163,6 @@ int	core_tmr_alloc_req(struct se_cmd *, void *, u8, gfp_t);
 void	core_tmr_release_req(struct se_tmr_req *);
 int	transport_generic_handle_tmr(struct se_cmd *);
 void	transport_generic_request_failure(struct se_cmd *, sense_reason_t);
-void	__target_execute_cmd(struct se_cmd *);
 int	transport_lookup_tmr_lun(struct se_cmd *, u64);
 void	core_allocate_nexus_loss_ua(struct se_node_acl *acl);